<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>表格</title>
    <style>
        /* 对tr设置边框是无用的 */
        table,th,td{
            border:1px solid #333;
           
        }
        table{
            width:300px;
            text-align: center;
            font-size: 20px;
    
            /* (核心)core border-collapse 边框折叠 */
            border-collapse: collapse;
        }
    </style>
</head>
<body>
    <table>
        <!-- 表头 -->
        <thead>
            <td  colspan="2" bgcolor=rgb(255,255,255)>商城</td>
            <!-- table row(行) -->
        </thead>
            <tr>
                <!-- table head （头）-->
                <th >商城</th>
                <th>iphone</th>
            </tr>
        <tr>
            <td >京东</td>
            <td>小米</td>
        </tr>
        <tr>
            <td>唯品会</td>
            <td>魅族</td>
        </tr>
      
    </table>
</body>
</html>